Preliminary thermal expansion screening data for tuffs

A major variable in evaluating the potential of silicic tuffs for use in geologic disposal of heat-producing nuclear wastes is thermal expansion. Results of ambient-pressure linear expansion measurements on a group of tuffs that vary treatly in porosity and mineralogy are presente here. Thermal expansion of devitrified welded tuffs is generally linear with increasing temperature and independent of both porosity and heating rate. Mineralogic factors affecting behavior of these tuffs are limited to the presence or absence of cristobalite and altered biotite. The presence of cristobalite results in markedly nonlinear expansion above 200{sup 0}C. If biotite in biotite-hearing rocks alters even slightly to expandable clays, the behavior of these tuffs near the boiling point of water can be dominated by contraction of the expandable phase. Expansion of both high- and low-porosity tuffs containing hydrated silicic glass and/or expandable clays is complex. The behavior of these rocks appears to be completely dominated by dehydration of hydrous phases and, hence, should be critically dependent on fluid pressure. Valid extrapolation of the ambient-pressure results presented here to depths of interest for construction of a nuclear-waste repository will depend on a good understanding of the interaction of dehydration rates and fluid pressures, and of the effects of both micro- and macrofractures on the response of tuff masss

Preliminary thermal expansion screening data for tuffs

A major variable in evaluating the potential of silicic tuffs for use in geologic disposal of heat-producing nuclear wastes is thermal expansion. Results of ambient-pressure linear expansion measurements on a group of tuffs that vary treatly in porosity and mineralogy are presente here. Thermal expansion of devitrified welded tuffs is generally linear with increasing temperature and independent of both porosity and heating rate. Mineralogic factors affecting behavior of these tuffs are limited to the presence or absence of cristobalite and altered biotite. The presence of cristobalite results in markedly nonlinear expansion above 200{sup 0}C. If biotite in biotite-hearing rocks alters even slightly to expandable clays, the behavior of these tuffs near the boiling point of water can be dominated by contraction of the expandable phase. Expansion of both high- and low-porosity tuffs containing hydrated silicic glass and/or expandable clays is complex. The behavior of these rocks appears to be completely dominated by dehydration of hydrous phases and, hence, should be critically dependent on fluid pressure. Valid extrapolation of the ambient-pressure results presented here to depths of interest for construction of a nuclear-waste repository will depend on a good understanding of the interaction of dehydration rates and fluid pressures, and of the effects of both micro- and macrofractures on the response of tuff masss

Thermal aspects of waste emplacement in layered tuffs

The thermal response of layered tuffs in Yucca Mountain at NTS to radwaste emplacement at 711 m depth (Bullfrog tuff) was analyzed. Three in-situ boiling criteria were examined. No boiling is predicted for any burial depth with power densities up to 150 kW/acre. Allowable powerdensities are plotted vs depth below 711 m for both HLW and spent fuels. (DLC

Preliminary one-dimensional thermal analysis of waste emplacement in tuffs

One-dimensional calculations of near-field temperatures resulting from waste emplacement in a multiple-layered tuff stratigraphy are presented. Results indicate a marked sensitivity of peak temperatures to assignment of in-situ fluid pressure, geothermal-heat flux, waste type, and location of waste relative to a specific stratigraphic discontinuity. Under the criterion that allowable initial-power densities are limited by the occurrence of boiling at a distance of 10 m from emplaced waste, allowable power densities are calculated to range up to 150 kW/acre or more, depending upon geothermal heat flux and waste type

Inmate Recidivism as a Measure of Private Prison Performance

The growth of the private corrections industry has elicited interest in the comparative performance of state and private prisons. One way to measure the service quality of private prisons is to examine inmates' postrelease performance. Current empirical evidence is limited to four studies, all conducted in Florida. This analysis replicates and adds to the Florida measures in a different state and enhances previous methods. It uses data for a large cohort of Oklahoma state prison inmates released between 1997 and 2001. Controlling for known covariates, multivariate survival analysis revealed comparative rates of reincarceration for inmates in multiple exposure and comparison groups. These results are unique among prior studies on this topic; private prison inmates had a greater hazard of recidivism in all eight models tested, six of which were statistically significant. Finding no empirical support for claims of superior service from private corrections, the authors discuss policy implications and prospects for future research.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Preliminary one-dimensional thermal analysis of waste emplacement in tuffs

One-dimensional calculations of near-field temperatures resulting from waste emplacement in a multiple-layered tuff stratigraphy are presented. Results indicate a marked sensitivity of peak temperatures to assignment of in-situ fluid pressure, geothermal-heat flux, waste type, and location of waste relative to a specific stratigraphic discontinuity. Under the criterion that allowable initial-power densities are limited by the occurrence of boiling at a distance of 10 m from emplaced waste, allowable power densities are calculated to range up to 150 kW/acre or more, depending upon geothermal heat flux and waste type

A thirteenth century preacher's handbook Studies in MS Laud misc. 511

Includes bibliographical referencesAvailable from British Library Document Supply Centre- DSC:DX222314 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo